The League had no actual power to punish the nations. All nations that
signed onto the league had to ban war, but when Japan and Italy wanted
to expand they simply left the league when it tried to stop them.
The League depended on the Great Powers to enforce its rulings (mostly
Britain and France) both were reluctant to use military force. They
economic sanctions levied by the League also failed since the affected
nations could simply trade with nonmembers.